Startup-time control apparatus and stop-time control apparatus of internal combustion engine, and control methods thereof, and record medium

ABSTRACT

If it is determined that the present engine startup is a high-temperature startup, immediately fuel injection in concert with start of cranking is prohibited. After a delay time elapses following the start of cranking, or when THC&lt;THCh is satisfied, fuel injection is started. Therefore, the cranking during the delay time cools interior of the combustion chambers. Since fuel injection starts after the cooling, pre-ignition can be prevented.

INCORPORATION BY REFERENCE

[0001] The disclosure of Japanese Patent Application No. 2001-274697filed on September 11 including the specification, drawings and abstractare incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The invention relates to a startup-time control apparatus and astop-time control apparatus in an internal combustion engine in whichfuel is injected into a combustion chamber, and also relates to controlmethods of the apparatuses, and a record medium storing the controlmethods.

[0004] 2. Description of the Related Art

[0005] A known related-art technology is an automatic stop-startapparatus that automatically stops an internal combustion engine whenthe vehicle is in a stopped state, for example, for a traffic signal orthe like, and that automatically starts up the engine for a start of thevehicle upon an operation for a vehicle run, for the purpose ofimproving fuel economy and reducing emissions. In a known system, theabove-described automatic stop-start apparatus is combined with adirect-injection type gasoline engine, that is, an internal combustionengine in which fuel is injected into a combustion chamber (JapanesePatent Application Laid-Open No. 2000-328979).

[0006] When an internal combustion engine stops operating, the waterpump driven by the engine also stops. Therefore, after a stop ofoperation of the engine, the temperature inside the combustion chambersdoes not immediately fall, but temporarily remains high because thecooling by the water pump is not performed. In a construction where anautomatic stop-start apparatus as described above is adopted, theautomatic stop duration from an automatic stop to an automatic starttends to be considerably shorter than a manual stop duration. Therefore,in many cases, the temperature in the combustion chambers is high at thetime of an automatic start.

[0007] If a direct-injection type internal combustion engine is startedwhile the combustion chamber temperature is high, fuel is injected fromfuel injection valves into high-temperature combustion chamberssimultaneously with the cranking. Therefore, there is a danger ofpre-ignition.

[0008] The problem of pre-ignition is not limited to the case of anautomatic startup performed by an automatic stop-start apparatus, butmay also occur at the time of a manual engine startup operationperformed by a driver if the duration from the stop to the startup ofthe engine is short so that the combustion chamber temperature remainshigh.

SUMMARY OF THE INVENTION

[0009] It is an object of the invention to prevent pre-ignition at thetime of a startup of a type of internal combustion engine in which fuelis injected into a combustion chamber.

[0010] In order to achieve the foregoing object, one aspect of theinvention provides a startup-time control apparatus of an internalcombustion engine in which fuel is injected into a combustion chamber,the control apparatus including: a high-temperature startup determiningportion that determines whether the internal combustion engine is in ahigh-temperature state at a time of startup of the internal combustionengine; and a fuel injection start timing setting portion that sets aninjection timing of an injection valve such that fuel injection startsafter a delay period elapses following a start of cranking if theinternal combustion engine is in the high-temperature state.

[0011] Another aspect of the invention provides a startup-time controlapparatus of an internal combustion engine in which fuel is injectedinto a combustion chamber, and in which an automatic stop-automaticstartup control of automatically stopping and restarting a combustionoperation upon satisfaction of an automatic stop condition and anautomatic start condition, respectively, is performed, the controlapparatus including: an automatic startup determining portion thatdetermines whether the combustion operation has been automaticallyrestarted; and a fuel injection start timing setting portion that setsan injection timing of an injection valve such that fuel injectionstarts after a delay period elapses following a start of cranking if thecombustion operation is automatically restarted.

[0012] Still another aspect provides a startup-time control apparatus ofan internal combustion engine in which fuel is injected into acombustion chamber, the internal combustion engine including: ahigh-temperature startup determining portion that determines whether theinternal combustion engine is in a high-temperature state at a time ofstartup of the internal combustion engine; and a startup-time fuelinjection amount setting portion that sets a smaller amount of fuelinjection at a time of startup if the high-temperature startupdetermining portion determines that the internal combustion engine is inthe high-temperature state at the time of startup than if the internalcombustion engine is not in the high-temperature state at the time ofstartup.

[0013] A further aspect of the invention provides a startup-time controlapparatus of an internal combustion engine in which fuel is injectedinto a combustion chamber, and in which an automatic stop-automaticstartup control of automatically stopping and restarting a combustionoperation upon satisfaction of an automatic stop condition and anautomatic start condition, respectively, is performed, the controlapparatus including: an automatic startup determining portion thatdetermines whether the combustion operation has been automaticallyrestarted; and a startup-time fuel injection amount setting portion thatsets a less amount of fuel injection when the combustion operation isautomatically restarted than at the time of startup caused by a startupoperation performed by an operator.

[0014] A still further aspect provides a startup-time control apparatusin which fuel injection into a combustion chamber and fuel injectioninto an intake passage are possible, the control apparatus including: ahigh-temperature startup determining portion that determines whether theinternal combustion engine is in a high-temperature state at a time ofstartup of the internal combustion engine; and a startup-time fuelinjection selecting portion which accomplishes the fuel injection at thetime of startup by performing the fuel injection into the combustionchamber or the fuel injection into both the combustion chamber and theintake passage if the internal combustion engine is not in thehigh-temperature state at the time of startup, and which accomplishesthe fuel injection at the time of startup by performing the fuelinjection into the intake passage if the internal combustion engine isin the high-temperature state at the time of startup.

[0015] A yet further aspect provides a startup-time control apparatus ofan internal combustion engine in which fuel injection into a combustionchamber and fuel injection into an intake passage are possible, and inwhich an automatic stop-automatic startup control of automaticallystopping a combustion operation if an automatic stop condition is met,and of automatically restarting the combustion operation if an automaticstart condition is met, is performed, the control apparatus including:an automatic startup determining portion that determines whether thecombustion operation has been automatically restarted; and astartup-time fuel injection selecting portion which accomplishes thefuel injection at the time of startup by performing the fuel injectioninto the combustion chamber or the fuel injection into both thecombustion chamber and the intake passage if the startup is other than acase where the combustion operation is automatically restarted, andwhich accomplishes the fuel injection at the time of startup byperforming the fuel injection into the intake passage if the combustionoperation is automatically restarted.

[0016] A further aspect of the invention provides a stop-time controlapparatus of an internal combustion engine in which fuel is injectedinto a combustion chamber, and in which an automatic stop-automaticstartup control of automatically stopping a combustion operation if anautomatic stop condition is met, and of automatically restarting thecombustion operation if an automatic start condition is met, isperformed, the control apparatus including: a high-temperature stopdetermining portion that determines whether the internal combustionengine is in a high-temperature state when the automatic stop conditionis met; and an automatic stop execution control portion which executesautomatic stop of the combustion operation if it is determined that theinternal combustion engine is not in the high-temperature state when theautomatic stop condition is met, and which prohibits the automatic stopof the combustion operation if it is determined that the internalcombustion engine is in the high-temperature state when the automaticstop condition is met.

[0017] A further aspect of the invention provides a stop-time controlapparatus of an internal combustion engine in which fuel is injectedinto a combustion chamber, and in which an automatic stop-automaticstartup control of automatically stopping a combustion operation if anautomatic stop condition is met, and of automatically restarting thecombustion operation if an automatic start condition is met, isperformed, the control apparatus including: an automatic stopdetermining portion that determines whether the combustion operation hasbeen automatically stopped; and a pre-startup cooling portion thatdrives a cooling device of the internal combustion engine during anautomatically caused stop of the combustion operation.

[0018] A further aspect provides a startup-time control apparatus of aninternal combustion engine in which fuel is injected into a combustionchamber, including: a high-temperature startup determining portion thatdetermines whether the internal combustion engine is in ahigh-temperature state at a time of startup; and a pre-fuel injectionsetting portion that sets an injection timing of an injection valve suchthat fuel is injected into the combustion chamber prior to cranking ifthe high-temperature startup determining portion determines that theinternal combustion engine is in the high-temperature state at the timeof startup.

[0019] A further aspect provides a startup-time control apparatus of aninternal combustion engine in which fuel is injected into a combustionchamber, and in which an automatic stop-automatic startup control ofautomatically stopping a combustion operation if an automatic stopcondition is met, and of automatically restarting the combustionoperation if an automatic start condition is met, is performed, thecontrol apparatus including: an automatic startup determining portionthat determines whether the combustion operation has been automaticallyrestarted; and a pre-fuel injection setting portion that sets aninjection timing of an injection valve such that fuel is injected intothe combustion chamber prior to cranking at the time of automaticstartup.

[0020] A further aspect provides a stop-time control apparatus of aninternal combustion engine in which fuel is injected into a combustionchamber, including: a high-temperature determining portion thatdetermines whether the internal combustion engine is in ahigh-temperature state; and a during-stop fuel injection setting portionthat sets an injection timing of an injection valve such that fuel isinjected into the combustion chamber if the high-temperature determiningportion determines that the internal combustion engine is in thehigh-temperature state during a stop of rotation of the internalcombustion engine.

[0021] A further aspect provides a stop-time control apparatus of aninternal combustion engine in which fuel is injected into a combustionchamber, and in which an automatic stop-automatic startup control ofautomatically stopping a combustion operation if an automatic stopcondition is met, and of automatically restarting the combustionoperation if an automatic start condition is met, is performed, thecontrol apparatus including a stop-time fuel injection setting portionthat sets an injection timing of an injection valve such that fuel isinjected into the combustion chamber immediately after an automaticallycaused stop of rotation of the internal combustion engine.

[0022] Furthermore, in order to achieve the foregoing object, there areprovided methods in which process based on the above-describedconstructions are performed, and record media storing the methods.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The foregoing and further objects, features and advantages of theinvention will become apparent from the following description ofpreferred embodiments with reference to the accompanying drawings,wherein like numerals are used to represent like elements and wherein:

[0024]FIG. 1 is a diagram illustrating a system construction of avehicular internal combustion engine and a control apparatus thereof inaccordance with Embodiment 1;

[0025]FIG. 2 is a flowchart illustrating an engine startup-time fuelinjection start delaying process executed by an engine ECU in Embodiment1;

[0026]FIG. 3 is a timing chart indicating an example of processing inEmbodiment 1;

[0027]FIG. 4 is a timing chart indicating an example of processing inEmbodiment 1;

[0028]FIG. 5 is a flowchart illustrating an engine startup-time fuelinjection start delaying process executed by an engine ECU in Embodiment2;

[0029]FIG. 6 is a flowchart illustrating an engine startup-time fuelinjection start delaying process executed by an engine ECU in Embodiment3;

[0030]FIG. 7 illustrates the construction of a map used in the processillustrated in FIG. 6;

[0031]FIG. 8 is a flowchart illustrating an engine startup-time fuelinjection amount reducing process executed by an engine ECU inEmbodiment 4;

[0032]FIG. 9 illustrates the construction of a map used in the processillustrated in FIG. 8;

[0033]FIG. 10 illustrates a construction of a fuel supply system inEmbodiment 5;

[0034]FIG. 11 is a flowchart illustrating an engine startup-time fuelinjection control process executed by an engine ECU in Embodiment 6;

[0035]FIG. 12 illustrates a construction of a fuel supply system inEmbodiment 7;

[0036]FIG. 13 is a flowchart illustrating an engine startup-time fuelinjection control process executed by an engine ECU in Embodiment 6;

[0037]FIG. 14 is a flowchart illustrating an engine automatic stopprocess executed by an eco-run ECU in Embodiment 7;

[0038]FIG. 15 is a flowchart illustrating an automatic stop-time waterpump driving process executed by an eco-run ECU in Embodiment 8;

[0039]FIG. 16 is a flowchart illustrating an engine startup-time fuelinjection control process executed by an engine ECU in Embodiment 9;

[0040]FIG. 17 is a flowchart illustrating an engine startup-time fuelinjection control process executed by an engine ECU in Embodiment 10;

[0041]FIG. 18 is a flowchart illustrating an engine stop-time fuelinjection control process executed by an engine ECU in Embodiment 11;and

[0042]FIG. 19 is a flowchart illustrating an engine stop-time fuelinjection control process executed by an engine ECU in Embodiment 12.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0043] [Embodiment 1]

[0044]FIG. 1 is a diagram illustrating a system construction of avehicular internal combustion engine and a control apparatus thereof towhich the invention is applied. In this embodiment, the internalcombustion engine is a direct injection-type gasoline engine(hereinafter, referred to as “engine”) 2.

[0045] Output of the engine 2 is transferred to the side of an outputshaft 6 a via a crankshaft 2 a, a torque converter 4, an automatictransmission (hereinafter, referred to as “AT”) 6, and is finallytransferred to wheels. Separately from this power transfer train fromthe engine 2 to the wheel, output of the engine 2 (torque) is alsotransferred to a belt 14 via a pulley 10 connected to the crankshaft 2a. The torque transferred to the belt 14 rotates other pulleys 16, 18.The pulley 10 is provided with an electromagnetic clutch 10 a. Theelectromagnetic clutch 10 a is switched on (engaged) or switched off(disengaged) in accordance with need, thus allowing selection oftransfer or non-transfer of output between the pulley 10 and thecrankshaft 2 a.

[0046] Of the pulleys 16, 18, the pulley 16 is connected with a rotationshaft of an accessory 22, whereby the accessory 22 can be driven bytorque transferred from the belt 14. The accessory 22 may be, forexample, an airconditioner compressor, a power steering pump, anengine-cooling water pump, etc. Although only one accessory 22 is shownin FIG. 1, there are various accessories in a real construction, forexample, an airconditioner compressor, a power steering pump, anengine-cooling water pump, etc, and each accessory is provided with adedicated pulley that is disposed so as to turn in cooperation with thebelt 14. Although not shown, the airconditioner compressor is providedwith a clutch that is switched on (engaged) or switched off (disengaged)in accordance with need, and thus allows selection of transfer ornon-transfer of output between the pulley 16 and the airconditionercompressor.

[0047] The pulley 18 drivingly connects the belt 14 to a motor-generator(hereinafter, referred to as “MG”) 26. The MG 26 functions as anelectric generator (“generative mode” or “regenerative mode”) whenneeded, so as to convert torque transferred from the engine 2 via thepulley 18 into electric energy. The MG 26 also functions as an electricmotor (“drive mode”) when needed, so as to turn the belt 14 via thepulley 18 and therefore drive one or both of the engine 2 and theaccessory 22.

[0048] The MG 26 is electrically connected to an inverter 28. When theMG 26 is in the generative mode or the regenerative mode, the inverter28 is switched so as to charge electric energy from the MG 26 into ahigh-voltage power supply (42 V in this embodiment) battery 30, and intoa low-voltage power supply (14 V in this embodiment) battery 34 via aDC/DC converter 32, and so as to form a power supply for an ignitionsystem, meters and the like, various ECUs (electronic control units),etc.

[0049] When the MG 26 is in the “drive mode”, the inverter 28 supplieselectric power from the high-voltage power supply battery 30 to the MG26 to drive the MG 26. Thus, the accessory 22 is driven during a stop ofthe engine, and the crankshaft 2 a can be rotated at the time ofautomatic startup or automatic stop of the engine, or at the time ofdrive-away of the vehicle. The inverter 28 is able to adjust therotation speed of the MG 26 by adjusting the supply of electric energyfrom the high-voltage power supply battery 30 to the MG 26.

[0050] A starter 36 is provided for starting the engine at the time of acold startup. The starter 36, supplied with power from the low-voltagepower supply battery 34, is able to start the engine 2 by turning a ringgear.

[0051] A cylinder head of the engine 2 is provided with fuel injectionvalves 37 that inject fuel directly into combustion chambers. The fuelinjection valves 37 are supplied with fuel via a delivery pipe 38 thatreceives high-pressure fuel from a high-pressure fuel pump (not shown).If the fuel injection valves 37 are controlled so that an amount of fuelcorresponding to a stoichiometric air-fuel ratio is supplied from thedelivery pipe 38 directly into each combustion chamber during the intakestroke, fuel is uniformly dispersed in the entire space of eachcombustion chamber, and is then ignited by an ignition plug 42. Thus,uniform combustion at the stoichiometric air-fuel ratio is accomplished.If the fuel injection valves 37 are controlled so that an amount of fuelthat is less than the amount corresponding to the stoichiometricair-fuel ratio is supplied from the delivery pipe 38 into eachcombustion chamber during a late stage of the compression stroke, fuelis ignited by the ignition plug 42 while being in a stratified state,without being uniformly dispersed in the entire combustion chamberspace. Thus, stratified charge combustion is accomplished. The uniformcombustion mode and the stratified charge combustion mode are selectedin accordance with the state of operation of the engine 2. It is alsopossible to omit the stratified charge combustion but perform only theuniform combustion despite the provision of the fuel injection valves 37for injecting fuel directly into the combustion chambers.

[0052] The AT 6 is provided with an electric oil pressure pump 44 thatis supplied with electric power from the low-voltage power supplybattery 34. The electric oil pressure pump 44 supplies hydraulic fluidto a hydraulic control portion provided in the AT 6. The hydraulicfluid, controlled by control valves provided in the hydraulic controlportion, adjusts the state of operation of clutches, brakes, and one-wayclutches provided in the AT 6, so as to change the state of speed shiftin accordance with need.

[0053] The aforementioned switching between the on and off states of theelectromagnetic clutch 10 a, the rotation speed control of the MG 26,the mode control of the inverter 28, the control of the starter 36, thestate-of-charge control of the batteries 30, 34, etc., which are relatedto the automatic stop or the automatic start, are performed by aneco-run ECU 40. The eco-run ECU 40 sets the generative mode while theengine 2 is driven. When the engine 2 is decelerating, the eco-run ECU40 sets the regenerative mode, and selects the on-state of theelectromagnetic clutch 10 a so that the MG 26 is turned by torque fromthe engine 2. Furthermore, at the time of starting up the engine 2, theeco-run ECU 40 sets the drive mode, and selects the on-state of theelectromagnetic clutch 10 a so that the engine 2 is turned by drivepower from the MG 26. While the engine 2 is in the automatic stoppedstate, the eco-run ECU 40 maintains the drive mode, and selects theoff-state of the electromagnetic clutch 10 a so that some accessories22, such as the airconditioner compressor, the power steering pump,etc., can be driven by the MG 26 when needed.

[0054] The switching on and off of accessories 22 excluding the waterpump, the combustion mode switch control, the fuel injection controlusing the fuel injection valves 37, the control of the opening of athrottle valve 48 provided in an intake pipe 2 b that is performed byusing an electric motor 46, and other engine controls are executed by anengine ECU 50. The drive control of the electric oil pressure pump 44and the speed shift control of the AT 6 are performed by a speed shiftcontrolling ECU (not shown).

[0055] The eco-run ECU 40 detects the rotation speed of the rotationshaft of the MG 26 from a rotation speed sensor provided in the MG 26,and detects the presence or absence of an eco-run system start commandmade by a driver from an eco-run switch, and also detects other data.The engine ECU 50 detects various data for the engine control and thelike, such as the engine cooling water temperature THW from a watertemperature sensor 51 provided in a cylinder block or a cylinder head,the amount of accelerator operation ACCP from an accelerator operationamount sensor, the vehicle speed SPD from a vehicle speed sensor, thedegree of throttle opening TA from a throttle opening sensor 48 a, theshift position SHFT from a shift position sensor, the engine rotationspeed NE from an engine rotation speed sensor, the intake pressure PMfrom an intake pressure sensor 49 provided in a surge tank 2 c, the fuelpressure of the delivery pipe 38 from a fuel pressure sensor, etc.

[0056] Each of the ECUs 40, 50 has a microcomputer as a centralcomponent in which a CPU executes necessary processing in accordancewith programs written in an internal ROM, and executes various controlsbased on results of processing. Results provided by processing and datadetected as described above are exchanged between the ECUs 40, 50, whichare capable of data communication therebetween. Therefore, the ECUs 40,50 are able to execute controls in cooperation.

[0057]FIG. 2 shows a flowchart illustrating an engine startup-time fuelinjection start delaying process executed by the engine ECU 50. Thisprocess is executed at every 120° CA (crank angle) of the crankshaft 2 aafter a main switch is turned on by an ignition switch. Steps in theflowchart corresponding to separate processing contents are representedby “S”.

[0058] When the process starts, it is first determined whether theengine startup (including an automatic start and a manual start causedby the ignition switch) is completed (S110). For example, it isdetermined that the startup is completed, if the engine rotation speedNE becomes 500 rpm or higher.

[0059] If the startup is not completed (“YES” at S110), it is thendetermined whether the combustion chamber temperature THC is higher thanor equal to a high-temperature criterion THCh (S120). The combustionchamber temperature THC represents the temperature of an inner wallportion of a combustion chamber estimated from an operation history ofthe engine 2. Specifically, the engine ECU 50 estimates the combustionchamber temperature THC by executing a computation process ofperiodically integrating the heat balance of the amount of heatgenerated in association with combustion of fuel injected duringoperation of the engine, the amount of heat released due to externaltemperature and circulation of cooling water, the amount of heatabsorbed by intake air, etc.

[0060] If THC<THCh (“NO” at S120), fuel injection from the fuelinjection valves 37 into the combustion chambers is permitted (S170),and then the process temporarily ends.

[0061] Conversely, if THC≧THCh (“YES” at S120), which means ahigh-temperature state in the combustion chambers, it is then determinedwhether the cranking is being performed (S130). It is determined thatthe cranking is being performed, if in the case of automatic start, thecontrol mode-indicating signal transmitted from the eco-run ECU 40indicates an automatic start mode. It is determined that the cranking isbeing performed, if in the case of manual start, the ignition switch isat a starter position. If the cranking is not being performed (“NO” atS130), fuel injection from the fuel injection valves 37 into thecombustion chambers is prohibited (S160). Then, the process temporarilyends.

[0062] Conversely, if the cranking is being performed (“YES” at S130),it is then determined whether a counter C is smaller than a referencedelay value Cw corresponding to the delay time (S140). The referencedelay value Cw is set as a value corresponding to a length of time thatis needed for the cooling water present outside the engine immediatelyprior to the start of cranking to reach a surrounding of the combustionchambers and reduce the temperature in the combustion chambers.

[0063] The counter C is set at “0” at the time of startup of the engineECU 50 or in step S180 described below. Therefore, during an initialperiod, C<Cw holds (“YES” at S140), so that the counter C is incremented(S150), and the prohibition of fuel injection from the fuel injectionvalves 37 into the combustion chambers is continued (S160). Then, theprocess temporarily ends.

[0064] As long as the state where the determination of “YES” is made insteps S110, S120, S130 and S140 continues, the prohibition of fuelinjection (S160) continues, so that fuel injection from the fuelinjection valves 37 is not performed despite the cranking. Therefore,the water pump, that is, an accessory 22, is driven by the MG 26 or thestarter 36 to circulate cooling water and thereby cool the engine 2.Furthermore, only external air supplied from the intake pipe 2b—sidepasses through the combustion chambers. Hence, the combustion chambersare efficiently cooled.

[0065] If C=Cw is reached (“NO” at S140) due to repeated increments instep S150, fuel injection is permitted (S170). As fuel injection fromthe fuel injection valves 37 thus starts, combustion starts in thecombustion chambers. Then, the engine 2 enters a complete combustionstate, and the engine rotation speed NE rises, so that the enginestartup is completed (“NO” at S110). Then, the counter C is set at “0”(S180). After that, the fuel injection-permitted state continues (S170).

[0066] If THC<THCh is reached (“NO” at S120) before C=Cw, fuel injectionfrom the fuel injection valves 37 into the combustion chambers ispermitted (S170), so that combustion starts in the combustion chambers.Upon completion of the startup (“NO” at S110), the counter C is set at“0” (S180). After that, the fuel injection-permitted state continues(S170).

[0067]FIGS. 3, 4 are timing charts indicating examples of controlperformed in this embodiment. FIG. 3 indicates a case where THC<THCh issatisfied at the time of initiation of the engine startup by the starter36. At a time point t0 when the cranking is started, the determinationof “NO” in step S120 (THC<THCh) is immediately made, so that fuelinjection is permitted (S170). Therefore, fuel injection from the fuelinjection valves 37 into the combustion chamber is immediately started.Hence, the engine 2 promptly reaches the complete combustion state, sothat at a time point t1, the engine rotation speed NE≧500 rpm is reachedand the startup is completed.

[0068]FIG. 4 indicates a case where THC≧THCh is satisfied at the time ofthe automatic engine startup by the MG 26. Although the cranking isstarted at a time point t10, fuel injection is prohibited in step S160,so that fuel injection from the fuel injection valves 37 is notperformed. At a time point t11 of elapse of a time corresponding to thereference delay value Cw from the start of the cranking, fuel injectionfrom the fuel injection valves 37 is started. Thus, during the periodfrom t10 to t11, cooling water circulates and only external air passesthrough the combustion chambers without combustion, so that thecombustion chambers are efficiently cooled. Due to fuel injectionperformed after the time point t11, the engine 2 promptly reachescomplete combustion. At a time point t12, the engine rotation speedNE≧500 rpm is reached, and the engine startup is completed. A similarprocess occurs in the case of a manual startup using the starter 36.

[0069] In the above-described construction, steps S110 to S130correspond to a process performed by a high-temperature startupdetermining portion, and steps S140 to S170 correspond to a processperformed by a fuel injection start timing setting portion.

[0070] According to Embodiment 1, the following advantages are achieved.

[0071] (a) As described above, if it is determined that the presentstartup is a high-temperature startup (“YES” at S120), immediate fuelinjection upon start of the cranking is prohibited (“YES” at S140followed by step S160). Fuel injection is started (S170) after the delayperiod elapses following the start of the cranking (“NO” at S140), orwhen THC<THCh is satisfied (“NO” at S120). Therefore, the crankingduring the delay period cools the interior of the combustion chambers.Since fuel injection is started after the cooling, spontaneous ignitionof mixture prior to spark ignition is prevented as fuel is injecteddirectly into the cooled combustion chambers. Thus, pre-ignition can beprevented both in the case of automatic startup and the case of a manualstartup caused by a driver.

[0072] (b) The reference delay value Cw is set as a value correspondingto a length of time that is needed for the cooling water present outsidethe engine immediately prior to the start of cranking to reach asurrounding of the combustion chambers and reduce the temperature in thecombustion chambers. Therefore, pre-ignition can be more effectivelyprevented.

[0073] [Embodiment 2]

[0074] This embodiment differs from Embodiment 1 in that the engine ECU50 executes an engine startup-time fuel injection start delaying processillustrated in FIG. at every 120° CA, instead of the process illustratedin FIG. 2. The engine startup-time fuel injection start delaying process(FIG. 5) is substantially the same as the process of FIG. 2, except thatstep S122 is executed in placed of step S120. Step S122 corresponds to aprocess performed by the automatic startup determining portion.

[0075] That is, if there is an incomplete startup state (“YES” at S110),it is then determined whether the startup is an automatic startup(S122). If the startup is not an automatic startup but is a manualstartup (“NO” at S122), fuel injection from the fuel injection valves 37is immediately permitted (S170). Then, the process temporarily endswithout any further processing.

[0076] Conversely, if the startup is an automatic startup (“YES” atS122), the process of steps S130 to S160 is executed as described abovein conjunction with Embodiment 1, whereby during a period correspondingto the reference delay value Cw, fuel injection from the fuel injectionvalves 37 is not performed but only the cranking by the MG 26 isperformed. If C=Cw is reached (“NO” at S140), fuel injection from thefuel injection valves 37 is performed (S170). Therefore, combustionstarts as is also illustrated in FIG. 4. After that, the startup iscompleted (“NO” at S110).

[0077] In the above-described construction, the engine startup-time fuelinjection start delaying process (FIG. 5) corresponds to a processperformed by the fuel injection start timing setting portion.

[0078] According to Embodiment 2 described above, the followingadvantages are achieved.

[0079] (a) Particularly in this engine 2, if the automaticstop-automatic startup is performed, the interval from the automaticstop to the automatic start is generally short, so that there occurs ahigh incidence of engine startup at a timing at which the combustionchamber temperature is high after the circulation of cooling water isstopped. Therefore, if it is determined that the startup is an automaticstart (“YES” at S122), immediate fuel injection upon start of crankingis prohibited (S160). After the delay period elapses following the startof cranking (“NO” at S140), fuel injection is started (S170). Thus, thecranking during the delay period cools the interior of the combustionchambers, thereby preventing pre-ignition, as mentioned above.

[0080] (b) It is not necessary to compute the combustion chambertemperature THC by periodically integrating the heat balance of theamount of heat generated, the amount of heat released, the amount ofheat absorbed, unlike Embodiment 1. Therefore, the computation load onthe engine ECU 50 is reduced. Thus, other processes can be more quicklyexecuted. It becomes also possible to construct the engine ECU 50 usinga low-cost CPU.

[0081] (c) An advantage the same as the advantage (b) of Embodiment 2can be achieved.

[0082] [Embodiment 3]

[0083] This embodiment differs from Embodiment 1 in that the engine ECU50 executes an engine startup-time fuel injection amount reducingprocess illustrated in FIG. 6 at every 120° CA, instead of the processillustrated in FIG. 2.

[0084] When the engine startup-time fuel injection amount reducingprocess (FIG. 6) starts, it is first determined whether there is astartup (including an automatic start and a manual startup) that is yetto be completed (S310). If there is an incomplete startup state (“YES”at S310), it is then determined whether cranking is being performed(S320). If cranking is not being performed (“NO” at S320), the processtemporarily ends without any further processing.

[0085] If cranking is being performed (“YES” at S320), it is thendetermined whether the combustion chamber temperature THC is higher thanor equal to the high-temperature criterion THCh (S330). If THC<THCh(“NO” at S330), a reducing correction value dQ for reducing the amountof fuel injection at the time of startup is set at “0 (mm³/oneinjection, which unit for the amount of fuel injection will be omittedbelow)” (S340). Then, the process temporarily ends. Therefore, in thiscase, the reducing correction using the reducing correction value dQ isnot performed with respect to the amount of fuel injection at the timeof startup.

[0086] Conversely, if THC≧THCh (“YES” at S330), a reducing correctionvalue dQ is computed based on the value of combustion chambertemperature THC with reference to a fuel injection amount reducing mapillustrated in FIG. 7 (S350). As is apparent from FIG. 7, the reducingcorrection value dQ is increased with increases in the combustionchamber temperature THC provided that the combustion chamber temperatureTHC is higher than or equal to the high-temperature criterion THCh.Therefore, within the range of THC≧THCh, if the combustion chambertemperature THC is higher, the amount of fuel injection at the time ofstartup becomes smaller.

[0087] Due to the reducing correction value dQ set as described above,the amount of fuel injection is kept reduced until the startup iscompleted. When the startup is completed (“NO” at S310), an attenuatingprocess of decreasing the reducing correction value dQ if dQ≧0 isperformed (S360) in every control cycle until the reducing correctionvalue dQ reaches “0”. If the reducing correction value dQ=0 initiallyholds, the attenuating process of step S360 is not performed in effect.When the reducing correction value dQ=0 is reached, the substantialprocess of FIG. 6 ends.

[0088] In the above-described construction, the process of steps S310 toS330 corresponds to a process performed by the high-temperature startupdetermining portion, and step S350 corresponds to a process performed bythe startup-time fuel injection amount setting portion.

[0089] According to Embodiment 3 described above, the followingadvantages are achieved.

[0090] (a) If the startup is a high-temperature startup (“YES” at S330),the amount of fuel injection at the time of startup is reduced bysetting a reducing correction value dQ with reference to a map.Therefore, pre-ignition becomes less likely to occur, and even ifpre-ignition occurs, the amount of heat generated can be kept at areduced level. Hence, damage to the engine 2 can be reduced.

[0091] [Embodiment 4]

[0092] This embodiment differs from Embodiment 3 in that the engine ECU50 executes an engine startup-time fuel injection amount reducingprocess illustrated in FIG. 8 at every 120° CA, instead of the processillustrated in FIG. 6. The process of FIG. 8 differs from the process ofFIG. 6 in that step S332 is performed in place of step S330, and stepS352 is executed in place of step S350.

[0093] If there is an incomplete startup state (“YES” at S310) andcranking is being performed (“YES” at S320), it is then determinedwhether the startup is an automatic start (S332). If the startup is notan automatic start but is a manual start (“NO” at S332), the reducingcorrection value dQ is set at “0” (S340).

[0094] Conversely, if the startup is an automatic start (“YES” at S332),a reducing correction value dQ is computed based on the present enginecooling water temperature THW and a present engine stop duration counterEGSTP with reference to a reducing correction value dQ map indicated inFIG. 9. The engine stop duration counter EGSTP is a counter that theengine ECU 50 uses to measure the stop duration of the engine 2 at everyautomatic engine stop.

[0095] The temperature in the combustion chamber tends to increase withincreases in the engine cooling water temperature THW. With regard tothe stop duration of the engine 2, the combustion chamber temperaturetemporarily becomes high during an initial period of the stop. Afterthat, the combustion chamber temperature tends to become lower withincreases in the stop duration. Therefore, in a map indicated in FIG. 9,the reducing correction value dQ is set greater as the engine coolingwater temperature THW is higher, as indicated by contour lines, and thereducing correction value dQ is set so as to form peaks in a regionwhere the value of the engine stop duration counter EGSTP is small.

[0096] If the reduction of the amount of fuel injection using thereducing correction value dQ set as described above is continued and thestartup is completed (“NO” at S310), the reducing correction value dQattenuating process is executed (S360). When the reducing correctionvalue dQ=0 is reached, substantial process illustrated in FIG. 8 ends.

[0097] In the above-described construction, the engine startup-time fuelinjection amount reducing process (FIG. 8) corresponds to a processperformed by the startup-time fuel injection amount setting portion.

[0098] According to Embodiment 4 described above, the followingadvantages are achieved.

[0099] (a) If the automatic stop-automatic start is performed with theengine 2, the incidence of an engine startup at a timing at which thecombustion chamber becomes high increases. Therefore, if it isdetermined that the startup is an automatic start (“YES” at S332), theamount of fuel injection is reduced by setting a reducing correctionvalue dQ with reference to the map of FIG. 9. Hence, pre-ignitionbecomes unlikely to occur, and if pre-ignition occurs, damage to theinternal combustion engine can be reduced.

[0100] (b) An advantage the same as the advantage (b) of the Embodiment2 is achieved.

[0101] [Embodiment 5]

[0102] Fuel pumped from a fuel tank 60 by a feed pump 62 is pressurizedand is supplied to the delivery pipe 38 by a high-pressure pump 64 asindicated in FIG. 10. The engine ECU 50 detects the fuel pressure in thedelivery pipe 38 by using a fuel pressure sensor 38 a, and adjusts theamount of ejection from the high-pressure pump 64 to the delivery pipe38 so as to achieve a fuel pressure corresponding to the state ofoperation of the engine 2. The construction of this high-pressure fuelsupplying system is the same as that in Embodiment 1. This embodimentdiffers in construction from Embodiment 1 in that low-pressure fuelsupplied from the feed pump 62 is supplied to an auxiliary fuelinjection valve 66 provided in the surge tank 2 c. With thisconstruction, the engine ECU 50 is able to cause injection of fuel fromthe auxiliary fuel injection valve 66 into the surge tank 2 cindependently of fuel injection valves 37 for injecting fuel into thecombustion chambers.

[0103] Furthermore, This embodiment differs from Embodiment 1 in thatthe engine ECU 50 executes an engine startup-time fuel injection controlprocess illustrated in FIG. 11 at every 120° CA, instead of the processillustrated in FIG. 2.

[0104] The engine startup-time fuel injection control process (FIG. 11)will be described. When this process starts, it is first determinedwhether the startup is incomplete (S410). If a yet-to-be completedstartup state is present (“YES” at S410), it is then determined whetherthe combustion chamber temperature THC is higher than or equal to thehigh-temperature criterion THCh (S420). If THC<THCh (“NO” at S420), amain fuel injection amount QINJST injected from the fuel injectionvalves 37 and an auxiliary fuel injection amount QINJADD injected fromthe auxiliary fuel injection valve 66 are set based on the enginecooling water temperature THW with reference to a map indicated in FIG.12 (S430). The main fuel injection amount QINJST becomes greater at lowtemperatures. The auxiliary fuel injection amount QINJADD is provided ifthe engine cooling water temperature THW is less than or equal to alow-temperature criterion temperature THW1. The auxiliary fuel injectionamount QINJADD becomes greater with decreases in temperature. Thus, ifTHC<THCh, the fuel injection valves 37 and the auxiliary fuel injectionvalve 66 are caused to inject fuel at the time of a cold start(THW<THW1) in accordance with the engine cooling water temperature THW.In the other situations, fuel is injected from only the fuel injectionvalves 37.

[0105] If THC≧THCh (“YES” at S420), fuel injection from only theauxiliary fuel injection valve 66 is executed (S440), that is, an amountof fuel needed at the time of startup is injected from the auxiliaryfuel injection valve 66 into the surge tank 2 c. Therefore, during ahigh-temperature state of the combustion chambers, fuel is not injecteddirectly into the combustion chambers, but is supplied into thecombustion chambers via intake ports in the form of air-fuel mixture.

[0106] After that, the engine 2 reaches the complete combustion state,and the engine rotation speed NE rises, so that the startup is completed(“NO” at S410). Then, fuel injection only from the fuel injection valves37 into the combustion chambers is performed (S450).

[0107] In the above-described construction, steps S410, S420 correspondto a process performed by the high-temperature startup determiningportion, and steps S430, S440 correspond to a process performed by astartup-time fuel injection selecting portion.

[0108] According to Embodiment 5 described above, the followingadvantages are achieved.

[0109] (a) In the case of a high-temperature startup (“YES” at S420),fuel injection at the time of startup is accomplished by fuel injectionfrom the auxiliary fuel injection valve 66 into the surge tank 2 c. Theavoidance of direct fuel injection into the combustion chambers in thismanner makes pre-ignition unlikely. In the case where the startup is nota high-temperature startup (“NO” at S420), the fuel injection at thetime of startup can be accomplished by fuel injection into thecombustion chambers if temperature is not low, and by fuel injectioninto the combustion chambers and the intake passage if temperature islow (S430). Therefore, fuel can be supplied into the combustion chambersat an early stage, and combustion can be promptly started. At the timeof low temperature, fuel is injected from the auxiliary fuel injectionvalve 66 as well, so that fuel atomization becomes good and enginestartup characteristic improves.

[0110] [Embodiment 6]

[0111] This embodiment differs from Embodiment 5 in that the engine ECU50 executes an engine startup-time fuel injection control processillustrated in FIG. 13 at every 120° CA, instead of the process of FIG.11.

[0112] When the engine startup-time fuel injection control process (FIG.13) starts, it is first determined whether the startup is incomplete(S410). If an incomplete startup state is present (“YES” at S410), it isthen determined whether the startup is an automatic start (S422). If thestartup is not an automatic start (“NO” at S422), an amount of fuelneeded at the time of startup is injected from the fuel injection valves37 into the combustion chambers (S450).

[0113] Conversely, if the startup is an automatic start (“YES” at S422),fuel injection from only the auxiliary fuel injection valve 66 isexecuted (S440), so that an amount of fuel needed at the time of startupis injected from the auxiliary fuel injection valve 66 into the surgetank 2 c. Therefore, in the case of an automatic start where there is ahigh possibility that the combustion chambers have a high-temperaturestate, fuel is not injected directly into the combustion chambers, butis supplied into the combustion chambers via intake ports in the form ofair-fuel mixture.

[0114] After that, the engine 2 reaches the complete combustion state,and the engine rotation speed NE rises, so that the startup is completed(“NO” at S410). Then, fuel injection only from the fuel injection valves37 into the combustion chambers is performed (S450).

[0115] In the foregoing construction, the engine startup-time fuelinjection control process (FIG. 13) corresponds to a process performedby the startup-time fuel injection selecting portion.

[0116] According to Embodiment 6 described above, the followingadvantages are achieved.

[0117] (a) In the case of an automatic start (“YES” at S422), it ishighly possible that the combustion chambers have high temperature.Therefore, the fuel injection at the time of startup is accomplished byperforming fuel injection from the auxiliary fuel injection valve 66into the surge tank 2 c without performing fuel injection from the fuelinjection valves 37 (S440). The avoidance of direct fuel injection intothe combustion chambers in this manner makes pre-ignition unlikely.Furthermore, in the case of startup other than the automatic start (“NO”at S422), fuel is injected into the combustion chambers (S450).Therefore, fuel can be supplied into the combustion chambers at an earlystage, and combustion can be promptly started, so that engine startupcharacteristic will improve.

[0118] (b) An advantage the same as the advantage (b) of the Embodiment2 is achieved.

[0119] [Embodiment 7]

[0120] This embodiment differs from Embodiment 1 in that the engine ECU50 does not execute the process of FIG. 2 and the eco-run ECU 40repeatedly executes an engine automatic stop process illustrated in FIG.14 in cycles of a short time.

[0121] When the eco-run ECU 40 starts the engine automatic stop (FIG.14), it is first determined whether an automatic stop condition is met(S510). For example, it is determined that the automatic stop conditionis met if all the following conditions (1) to (5) are satisfied: (1) acondition that the engine 2 is already warmed up, but is not overheated(the engine cooling water temperature THW is lower than a watertemperature upper limit value, and is higher than a water temperaturelower limit value); (2) a condition that the accelerator pedal is notdepressed; (3) a condition that the states of charge of the batteries30, 34 are at respectively needed levels; (4) a condition that the brakepedal is not depressed; and (5) a condition that the vehicle is in astopped state (the vehicle speed SPD being 0 km/h).

[0122] If any one of the conditions (1) to (5) is unsatisfied, theautomatic stop condition is not met (“NO” at S510). Then, the processtemporarily ends.

[0123] Conversely, if the automatic stop condition is met due to, forexample, a driver stopping the vehicle at an intersection or the like(“YES” at S510), it is subsequently determined whether the combustionchamber temperature THC is less than a high-temperature predictioncriteria THCa (S520). The high-temperature prediction criteria THCa is acriterion value which is smaller than the high-temperature criterionTHCh, and which indicates that there is high possibility that if theengine is automatically stopped with the combustion chamber temperatureTHC being higher than or equal to the high-temperature predictioncriteria THCa, the combustion chamber temperature THC will be higherthan or equal to the high-temperature criterion THCh at the time ofautomatic start.

[0124] If THC<THCa (“YES” at S520), the automatic stop process isexecuted (S530), and then the process temporarily ends.

[0125] In this automatic stop process (S530), the eco-run ECU 40 outputsa fuel-cut command to the engine ECU 50, whereby the fuel injection fromthe fuel injection valves 37 and the throttle valve 48 is completelyclosed. Therefore, combustion in the combustion chambers stops, andrevolution of the engine 2 stops.

[0126] If THC≧THCa (“NO” at S520), the automatic stop (S530) is notexecuted, and the process temporarily ends without any furtherprocessing. Thus, if the automatic stop condition is met ((“YES” atS510), the automatic stop is avoided in a case where the combustionchamber temperature THC is at a relatively high level. In that case,therefore, the automatic start is not performed either.

[0127] In the above-described construction, steps S510, S520 correspondto a process performed by the high-temperature determining portion, andthe process of determining whether to perform the process of step S530depending on the determination made in step S520 corresponds to aprocess performed by an automatic stop execution control portion.

[0128] According to Embodiment 7 described above, the followingadvantages are achieved.

[0129] (a) If the engine 2 has relatively high temperature when theautomatic stop is to be executed, immediate execution of automatic stopwill highly likely lead to a further increased temperature in thecombustion chambers at the time of automatic start. Therefore, if at thetime of satisfaction of the automatic stop condition (“YES” at S510),the combustion chamber temperature THC is relatively high (“NO” atS520), execution of the automatic stop is prohibited, so that theautomatic start is not executed. Therefore, pre-ignition at the time ofautomatic start can be prevented.

[0130] [Embodiment 8]

[0131] This embodiment differs from Embodiment 1 in that the engine ECU50 does not execute the process of FIG. 2 and the eco-run ECU 40repeatedly executes an automatic stop-time water pump driving processillustrated in FIG. 15 in cycles of a short time.

[0132] When the automatic stop-time water pump driving process (FIG. 15)starts, it is first determined whether automatic stop is being executed(S610). If automatic stop is being executed (“YES” at S610), it issubsequently determined whether the engine cooling water temperature THWis higher than or equal to a cooling execution criterion THWb (S620).The cooling execution criterion THWb is a criterion for indicating thatthere is a possibility of pre-ignition at the time of automatic start ifthe engine cooling water temperature THW is lower than the coolingexecution criterion THWb.

[0133] If THW≧THWb (“YES” at S620), a water pump drive flag XWP is setto an “ON” state (S630), and the process temporarily ends. If the waterpump drive flag XWP is “ON”, the electromagnetic clutch 10 a isdisengaged by a separately-executed MG 26-driving process, and the MG 26is set in the drive mode where the MG 26 is operated by electric energyfrom the battery 30, and therefore drives the engine-cooling water pump,that is, an accessory 22, via the pulley 18, the belt 14 and the pulley16. If the MG 26 is already set in the drive mode due to a request fordriving the airconditioner compressor or the power steering pump, thedrive mode is continued. Therefore, even if rotation of the engine 2 isstopped, cooling water can be circulated in the engine 2 to reduce thecombustion chamber temperature THC.

[0134] Conversely, if THW<THWb (“NO” at S620), the water pump drive flagXWP is set to an “OFF” state (S640), and the process temporarily ends.

[0135] If the water pump drive flag XWP is set to the “OFF” state,rotation of the MG 26 is stopped, so that the engine-cooling water pumpis not driven. However, if there is a request for driving theairconditioner compressor or the power steering pump, the MG 26 operatesin the drive mode despite XWP=“OFF”.

[0136] In the above-described construction, step S620 corresponds to aprocess performed by a high-temperature determining portion, and stepsS610, S630 correspond to a process performed by a pre-startup coolingportion.

[0137] According to Embodiment 8 described above, the followingadvantages are achieved.

[0138] (a) If during the automatic stop, the engine cooling watertemperature THW is higher than or equal to the cooling executioncriterion THWb (“YES” at S620), execution of automatic start without anychange from the present state will highly likely cause per-ignition.Therefore, the engine 2 is cooled by the MG 26 actively driving theengine-cooling water pump (S630), so that the pre-ignition at the timeof automatic start can be prevented.

[0139] (b) An advantage the same as the advantage (b) in Embodiment 2 isachieved.

[0140] [Embodiment 9]

[0141] This embodiment differs from Embodiment 1 in that the engine ECU50 repeated executes an engine startup-time fuel injection controlprocess illustrated in FIG. 16 in short-time cycles, instead of theprocess illustrated in FIG. 2.

[0142] When the engine startup-time fuel injection control process (FIG.16) starts, it is determined whether an incomplete startup is present(S710). If an incomplete startup state is present (“YES” at S710), it isthen determined whether there is a startup request (S720). If there isno request for an automatic start or a manual start (“NO” at S720),prohibition of cranking is set (S730), and then the process temporarilyends. The setting of prohibition of cranking is made so that if astartup request is output based on automatic startup or manual startup,the engine ECU 50 is allowed to turn the crankshaft 2 a by using the MG26 or the starter 36 only after a cranking permission setting (describedbelow) is made (S760).

[0143] Conversely, if there is a startup request (“YES” at S720), it issubsequently determined whether the combustion chamber temperature THCis higher than or equal to the high-temperature criterion THCh (S740).If THC<THCh (“NO” at S740), the cranking permission is immediately set(S760), and then the process temporarily ends. Thus, if the combustionchamber temperature THC is not in a high range, the presence of astartup request immediately permits cranking, so that cranking starts.

[0144] If THC≧THCh (“YES” at S740), fuel is subsequently injectedsimultaneously into all the cylinders from the fuel injection valves 37(S750). The purpose of this fuel injection is to cool thehigh-temperature combustion chambers by heat absorption involved inevaporation of fuel. The amount of fuel injected may be fixed, or may bevariably set in accordance with the combustion chamber temperature THC.Although at this moment, cranking is yet to be started and therefore thehigh-pressure fuel pump is not operated, simultaneous fuel injectionfrom the fuel injection valves 37 can be performed, if performed onlyonce, because sufficiently high residual pressure exists in the deliverypipe 38 at a timing when the combustion chambers have high temperature.

[0145] Then, cranking is immediately permitted (S760), and the processtemporarily ends. After that, when the startup is completed by cranking(“NO” at S710), substantial process of the engine startup-time fuelinjection control process (FIG. 16) ends.

[0146] In the foregoing construction, steps S710, S720 and S740correspond to a process performed by the high-temperature startupdetermining portion, and steps S730, S750 and S760 correspond to aprocess performed by a pre-fuel injection setting portion.

[0147] According to Embodiment 9 described above, the followingadvantages are achieved.

[0148] (a) In the case of a high-temperature startup (“YES” at S740),the combustion chambers can be cooled due to heat absorption involved inevaporation of the fuel supplied thereinto by injecting fuel into thecombustion chambers (S750) before cranking is performed for a startup.At the time of fuel injection prior to cranking, air-fuel mixture formedby injecting fuel into combustion chambers is not immediatelycompressed, but is allowed to sufficiently evaporate and absorb heat.Therefore, this fuel injection is able to make pre-ignition moreunlikely than the fuel injection performed during cranking.

[0149] [Embodiment 10]

[0150] This embodiment differs from Embodiment 9 in that the engine ECU50 repeatedly executes an engine startup-time fuel injection controlprocess illustrated in FIG. 17 in short-time cycles, instead of theprocess illustrated in FIG. 16. The process of FIG. 17 differs from theprocess of FIG. 16 in that step S742 is executed in place of step S740.

[0151] If there is a startup request (“YES” at S720), it is subsequentlydetermined whether the startup request is based on an automatic start(S742). If the startup request is based on a manual start (“NO” atS742), cranking is immediately permitted (S760), and the processtemporarily ends. Thus, in the case of manual start, the probability ofa high-temperature startup is considered to be low. Therefore, a startuprequest based on manual start is immediately followed by permission ofcranking, and therefore cranking is immediately started.

[0152] In the case of automatic start (“YES” at S742), fuel is injectedsimultaneously from the fuel injection valves 37 into all the cylinders(S750). The amount of fuel injected in this operation may be a fixedamount, or may be suitably set in accordance with an engine stopduration counter EGSTOP that measures the stop duration of the engine 2.For example, if the stop duration is several minutes or shorter, a fixedamount of fuel is injected. If the stop duration is longer than that,fuel injection is avoided. Such simultaneous fuel injection isaccomplished by residual pressure in the delivery pipe 38.

[0153] After the simultaneous fuel injection at step S750, cranking isimmediately permitted (S760), and then the process temporarily ends.After that, when the startup is completed by cranking (“NO” at S710),substantial process of the engine startup-time fuel injection controlprocess (FIG. 17) ends.

[0154] In the foregoing construction, the engine startup-time fuelinjection control process (FIG. 17) corresponds to a process performedby the pre-fuel injection setting portion. According to Embodiment 10described above, the following advantages are achieved.

[0155] (a) In the case of automatic start (“YES” at S742), fuel isinjected into the combustion chambers (S750) regardless of ahigh-temperature condition, before cranking is performed for thestartup. Therefore, heat absorption involved in evaporation of injectedfuel cools the combustion chambers, and therefore makes pre-ignitionless likely.

[0156] (b) An advantage the same as the advantage (b) of Embodiment 2 isachieved.

[0157] [Embodiment 11]

[0158] This embodiment differs from Embodiment 1 in that the engine ECU50 does not execute the process of FIG. 2, but repeatedly executes anengine stop-time fuel injection control process illustrated in FIG. 18in short-time cycles.

[0159] When the engine stop-time fuel injection control process (FIG.18) starts, it is first determined whether there is a stop request basedon automatic stop or manual stop (S810). If a stop request is notpresent (“NO” at S810), the process temporarily ends without any furtherprocessing.

[0160] If a stop request is present (“YES” at S810), it is subsequentlydetermined whether the engine 2 has stopped turning (S820). That is, itis determined that engine rotation has stopped, if, for example, 500msec elapses following discontinuation of engine rotation speedNE-corresponding pulse signals output by the engine rotation speedsensor. If engine rotation has not stopped (“NO” at S820), the processtemporarily ends without any further processing.

[0161] If engine rotation stops (“YES” at S820), it is subsequentlydetermined whether the engine cooling water temperature THW is higherthan or equal to a high-temperature criterion THWh (S830). Thehigh-temperature criterion THWh is a criterion for indicating that ifthe engine stops without any change from the present state, the dangerof pre-ignition will increase due to temperature rise in combustionchambers. If THW<THWh (“NO” at S830), the process temporarily endswithout any further processing.

[0162] If THW≧THWh (“YES” at S830), it is then determined (S840) whetherthe present execution is the first execution after the stop of enginerotation. If the present execution is the first execution (“YES” atS840), fuel injection is performed simultaneously with respect to allthe cylinders (S850), and the process temporarily ends. The purpose ofthis fuel injection is to cool the high-temperature combustion chambersin advance by heat absorption involved in evaporation of fuel. Theamount of fuel injected may be a fixed amount, or may be suitably set inaccordance with the combustion chamber temperature THC. In this case,too, the fuel injection is accomplished by residual pressure in thedelivery pipe 38.

[0163] In the subsequent cycle of control, the present execution is nolonger the first execution (“NO” at S840), and the process temporarilyends without any further processing. After that, the engine stop-timefuel injection control process (FIG. 18) is not substantially performeduntil a stop request is made again following a startup request.

[0164] In the foregoing construction, step S830 corresponds to a processperformed by the high-temperature determining portion, and steps S810,S820, S840 and S850 correspond to a process performed by a during-stopfuel injection setting portion.

[0165] According to Embodiment 11 described above, the followingadvantages are achieved.

[0166] (a) If the engine 2 is in a high-temperature state during a stopof engine rotation, an engine startup during the high-temperature statewill lead to high possibility of pre-ignition. Therefore, if during astop of engine rotation, the engine cooling water temperature THW ishigh, the combustion chambers are cooled in advance by injecting fuelinto the combustion chamber immediately after the stop of rotation ofthe engine. This cooling process reduces the likelihood of pre-ignitionoccurring at the time of startup. Since the combustion chambers arecooled by fuel injection immediately after a stop of the engine iftemperature is high at the time of stop, the engine can be started in acooled state regardless of the timing of output of a startup request.

[0167] (b) An advantage the same as the advantage (b) of Embodiment 2 isachieved.

[0168] [Embodiment 12]

[0169] This embodiment differs from Embodiment 11 in that the engine ECU50 repeatedly executes an engine stop-time fuel injection controlprocess illustrated in FIG. 19 in short-time cycles, instead of theprocess illustrated in FIG. 18. The process of FIG. 19 differs from theprocess of FIG. 18 only in that step S832 is executed in place of stepS830.

[0170] That is, if in response to a stop request (“YES” at S810), enginerotation stops (“YES” at S820), it is subsequently determined whetherthe engine stop is an automatic stop (S832). If the stop is a manualstop (“NO” at S832), the process temporarily ends without any furtherprocessing.

[0171] Conversely, if the engine stop is an automatic start (“YES” atS832), the process proceeds to step S840. Step 840 and step S850 aredescribed above in conjunction with Embodiment 11.

[0172] In the foregoing construction, the engine stop-time fuelinjection control process (FIG. 19) corresponds to a process performedby a stop-time fuel injection setting portion.

[0173] According to Embodiment 12 described above, the followingadvantages are achieved.

[0174] (a) Since a setting is made such that fuel is injected into thecombustion chambers immediately after the engine is stopped by automaticstop, it is possible to prevent a high-temperature state of the engine 2and prevent execution of automatic start during a high-temperaturestate. Therefore, the likelihood of pre-ignition is reduced.

[0175] (b) An advantage the same as the advantage (b) of Embodiment 2 isachieved.

[0176] [Other Embodiments]

[0177] Although in Embodiments 1 and 2, fuel injection is permittedafter rotation of a crank angle corresponding to the reference delayvalue Cw following the start of cranking, it is also possible to set atime-based delay period and permit fuel injection after the elapse ofthe delay period following the start of cranking.

[0178] Although in Embodiment 3, the reducing correction value dQ forthe high-temperature startup is set at greater values with increases intemperature, the reducing correction value dQ for the high-temperaturestartup may also be set at a fixed value.

[0179] Although in Embodiments 1, 3, 4, 5, 7 and 9, the combustionchamber temperature THC is estimated, the combustion chamber temperatureTHC may instead be directly detected by an in-combustion chambertemperature sensor provided in a cylinder head or a cylinder block.Furthermore, instead of the combustion chamber temperature THC, theengine cooling water temperature THW acquired from the water temperaturesensor 51 may be used. In this case, an advantage the same as theadvantage (b) of Embodiment 2 is achieved.

[0180] Although in Embodiment 8, only whether to drive the water pump iscontrolled based on the content of setting of the water pump drive flagXWP, it is also possible to adjust the rotation speed of the water pumpdriven by the MG 26 in accordance with the value of engine cooling watertemperature THW so that the rotation speed increases with increases inthe engine cooling water temperature THW.

[0181] Although in Embodiments 8 and 11, the engine cooling watertemperature THW is used, it is also possible to use the engine coolingwater temperature THW acquired by estimation or direct detection.Furthermore, during operation of the engine 2, it is also possible touse the exhaust temperature detected by an exhaust temperature sensorprovided in the exhaust passage, instead of the engine cooling watertemperature THW or the engine cooling water temperature THW.

[0182] In Embodiments 9 to 12, the fuel injection is accomplished byresidual pressure in the delivery pipe 38. However, if the high-pressurepump is an electric pump, or is provided as an accessory 22, thehigh-pressure pump can be driven by directly supplying electric powerthereto or using the MG 26, so that the aforementioned fuel injectioncan be accomplished without consumption of residual pressure in thedelivery pipe 38. Therefore, engine startup characteristic can beimproved.

[0183] The foregoing embodiments may be combined in any suitable manner.

[0184] Means for achieving the aforementioned objects, and operation andadvantages of the means will be stated below.

[0185] An internal combustion engine startup-time control apparatus is astartup-time control apparatus of an internal combustion engine in whichfuel is injected into a combustion chamber, and is characterized byincluding: a high-temperature startup determining portion thatdetermines whether the internal combustion engine is in ahigh-temperature state at a time of startup of the internal combustionengine; and a fuel injection start timing setting portion that sets aninjection timing of an injection valve such that fuel injection startsafter a delay period elapses following a start of cranking if thehigh-temperature startup determining portion determines that theinternal combustion engine is in the high-temperature state at the timeof startup.

[0186] If the high-temperature determining portion determines that thestartup is a high-temperature startup, the fuel injection start timingsetting portion does not immediately inject fuel upon the start ofcranking, but sets an injection timing of an injection valve such thatfuel injection is started after the delay period elapses following thestart of cranking. Therefore, during the delay period, cranking causescirculation of cooling water, and replacement of intake air in thecombustion chambers, thereby cooling the interior of the combustionchambers. After that, fuel injection is started. Since the combustionchambers have been cooled, direct fuel injection into the combustionchambers will not lead to ignition of air-fuel mixture prior to sparkignition. Therefore, pre-ignition can be prevented in both the case ofautomatic startup and the case of manual startup.

[0187] An internal combustion engine startup-time control apparatus is astartup-time control apparatus of an internal combustion engine in whichfuel is injected into a combustion chamber, and in which an automaticstop-automatic startup control of automatically stopping a combustionoperation if an automatic stop condition is met, and of automaticallyrestarting the combustion operation if an automatic start condition ismet, is performed. The control apparatus is characterized by including afuel injection start timing setting portion that sets an injectiontiming of an injection valve such that fuel injection starts after adelay period elapses following a start of cranking if the combustionoperation is automatically restarted.

[0188] In an internal combustion engine in which automaticstop-automatic start is performed, in particular, fuel injection may bestarted after the elapse of the delay period following the start ofcranking regardless of a high-temperature condition, when combustionoperation is automatically restarted, that is, at the time of automaticstartup. This is because in the case of automatic startup, there is highincidence of engine startup occurring during a high-temperature state ofthe combustion chamber. Therefore, pre-ignition can be prevented.

[0189] In either one of the constructions described above, the delayperiod may be a length of time that is needed for an engine coolingwater present outside the engine immediately prior to the start ofcranking to reach a surrounding of the combustion chamber and reduce atemperature in the combustion chamber.

[0190] By setting the delay period as a length of time that is neededbefore an engine cooling water present outside the engine immediatelyprior to the start of cranking reaches a surrounding of the combustionchamber and reduces a temperature in the combustion chamber,pre-ignition can be more reliably prevented.

[0191] An internal combustion engine startup-time control apparatus is astartup-time control apparatus of an internal combustion engine in whichfuel is injected into a combustion chamber, and is characterized byincluding: a high-temperature startup determining portion thatdetermines whether the internal combustion engine is in ahigh-temperature state at a time of startup of the internal combustionengine; and a startup-time fuel injection amount setting portion thatsets a smaller amount of fuel injection at a time of startup if thehigh-temperature startup determining portion determines that theinternal combustion engine is in the high-temperature state at the timeof startup than if the internal combustion engine is not in thehigh-temperature state at the time of startup.

[0192] Thus, in the case of high-temperature startup, reducing theamount of fuel injection makes pre-ignition unlikely and, ifpre-ignition occurs, reduces damage to the internal combustion engine.

[0193] An internal combustion engine startup-time control apparatus is astartup-time control apparatus of an internal combustion engine in whichfuel is injected into a combustion chamber, and in which an automaticstop-automatic startup control of automatically stopping a combustionoperation if an automatic stop condition is met, and of automaticallyrestarting the combustion operation if an automatic start condition ismet, is performed. The control apparatus is characterized by including astartup-time fuel injection amount setting portion that, if thecombustion operation is automatically restarted, sets an amount of fuelinjection at a time of startup as an amount that is smaller than theamount of fuel injection set at a time of startup caused by a startupoperation performed by an operator.

[0194] In an internal combustion engine in which automaticstop-automatic startup is performed, setting a smaller amount of fuelinjection at the time of automatic startup than at the time of manualstartup regardless of a high-temperature condition makes pre-ignitionunlikely and, if pre-ignition occurs, reduces damage to the internalcombustion engine.

[0195] An internal combustion engine startup-time control apparatus is astartup-time control apparatus in which fuel injection into a combustionchamber and fuel injection into an intake passage are possible, and ischaracterized by including: a high-temperature startup determiningportion that determines whether the internal combustion engine is in ahigh-temperature state at a time of startup of the internal combustionengine; and a startup-time fuel injection selecting portion whichaccomplishes the fuel injection at the time of startup by performing thefuel injection into the combustion chamber or the fuel injection intoboth the combustion chamber and the intake passage if thehigh-temperature startup determining portion determines that theinternal combustion engine is not in the high-temperature state at thetime of startup, and which accomplishes the fuel injection at the timeof startup by performing the fuel injection into the intake passage ifthe high-temperature startup determining portion determines that theinternal combustion engine is in the high-temperature state at the timeof startup.

[0196] Thus, in the case of high-temperature startup, fuel injection atthe time of startup is accomplished by fuel injection into the intakepassage. Since fuel is not directly injected into the combustionchambers, pre-ignition is unlikely to occur. If the startup is not ahigh-temperature startup, fuel injection at the time of startup can beaccomplished by fuel injection into the combustion chamber or fuelinjection into both the combustion chamber and the intake passage.Therefore, fuel can be supplied into the combustion chamber early, andcombustion can be promptly started. Hence, engine startup characteristiccan be improved. The expression “fuel injection into the combustionchamber and fuel injection into both the combustion chamber and theintake passage” includes a case where only the fuel injection into thecombustion chamber is performed, a case where only the fuel injectioninto both the combustion chamber and the intake passage is performed,and a case where the fuel injection into only the combustion chamber orthe fuel injection into both the combustion chamber and the intakepassage is selectively performed in accordance with need. This appliesin other constructions of the invention.

[0197] An internal combustion engine startup-time control apparatus is astartup-time control apparatus of an internal combustion engine in whichfuel injection into a combustion chamber and fuel injection into anintake passage are possible, and in which an automatic stop-automaticstartup control of automatically stopping a combustion operation if anautomatic stop condition is met, and of automatically restarting thecombustion operation if an automatic start condition is met, isperformed. The control apparatus is characterized by including astartup-time fuel injection selecting portion which accomplishes thefuel injection at the time of startup by performing the fuel injectioninto the combustion chamber or the fuel injection into both thecombustion chamber and the intake passage if the startup is other than acase where the combustion operation is automatically started, and whichaccomplishes the fuel injection at the time of startup by performing thefuel injection into the intake passage if the combustion operation isautomatically restarted.

[0198] In an internal combustion engine in which automaticstop-automatic start is performed, in particular, pre-ignition can bemade unlikely in the case of automatic start by accomplishing fuelinjection at the time of startup through fuel injection into the intakepassage, regardless of a high-temperature condition. At the time ofstartup other than automatic startup, fuel injection at the time ofstartup is accomplished by fuel injection into the combustion chamber orfuel injection into both the combustion chamber and the intake passage,so that fuel can be supplied into the combustion chamber early andcombustion can be promptly started. Therefore, engine startupcharacteristic can be improved.

[0199] An internal combustion engine stop-time control apparatus is astop-time control apparatus of an internal combustion engine in whichfuel is injected into a combustion chamber, and in which an automaticstop-automatic startup control of automatically stopping a combustionoperation if an automatic stop condition is met, and of automaticallyrestarting the combustion operation if an automatic start condition ismet, is performed. The control apparatus is characterized by including:a high-temperature stop determining portion that determines whether theinternal combustion engine is in a high-temperature state when theautomatic stop condition is met; and an automatic stop execution controlportion which executes automatic stop of the combustion operation if thehigh-temperature stop determining portion determines that the internalcombustion engine is not in the high-temperature state when theautomatic stop condition is met, and which prohibits the automatic stopof the combustion operation if the high-temperature stop determiningportion determines that the internal combustion engine is in thehigh-temperature state when the automatic stop condition is met.

[0200] In the case of an internal combustion engine in which automaticstop-automatic startup is performed, if the internal combustion engineis in the high-temperature state when the automatic stop condition ismet, automatic stop of the combustion operation, that is,generally-termed automatic stop, is prohibited. If the internalcombustion engine is already in the high-temperature state when theengine is to be stopped, execution of automatic stop without any changefrom the present state will lead to high possibility of furtherincreased temperature occurring in the combustion chamber at the time ofsubsequent automatic start. Therefore, by prohibiting the automaticstop, automatic start is avoided, so that pre-ignition at the time ofautomatic start is prevented.

[0201] An internal combustion engine stop-time control apparatus is astop-time control apparatus of an internal combustion engine in whichfuel is injected into a combustion chamber, and in which an automaticstop-automatic startup control of automatically stopping a combustionoperation if an automatic stop condition is met, and of automaticallyrestarting the combustion operation if an automatic start condition ismet, is performed. The control apparatus is characterized by including apre-startup cooling portion that drives a cooling device of the internalcombustion engine during an automatic stop of the combustion operation.

[0202] Since the cooling device of the internal combustion engine isdriven during an automatic stop, the interior of the combustion chamberis cooled, and therefore temperature drops. Therefore, at the time ofautomatic start, fuel is injected into the already cooled combustionchamber, so that pre-ignition can be prevented.

[0203] In the above-described construction of the internal combustionengine stop-time control apparatus, the pre-startup cooling portion maydrive the cooling device of the internal combustion engine by electricenergy.

[0204] If the cooling device of the internal combustion engine is drivenby using electric energy from, for example, a battery or the like, theinterior of the combustion chamber can be cooled even prior to thecranking of the engine, so that pre-ignition at the time of automaticstartup can be prevented.

[0205] The internal combustion engine stop-time control apparatus mayfurther include a high-temperature determining portion that determineswhether the internal combustion engine is in a high-temperature state,wherein the pre-startup cooling portion drives the cooling device of theinternal combustion engine if the high-temperature determining portiondetermines that the internal combustion engine is in thehigh-temperature state during an automatically-caused stop of thecombustion operation.

[0206] The case where the cooling device is driven may be limited to thecase where the internal combustion engine is in the high-temperaturestate. This reduces consumption of energy for driving the coolingdevice.

[0207] An internal combustion engine startup-time control apparatus is astartup-time control apparatus of an internal combustion engine in whichfuel is injected into a combustion chamber. The control apparatus ischaracterized by including: a high-temperature startup determiningportion that determines whether the internal combustion engine is in ahigh-temperature state at a time of startup; and a pre-fuel injectionsetting portion that sets an injection timing of an injection valve suchthat fuel is injected into the combustion chamber prior to cranking ifthe high-temperature startup determining portion determines that theinternal combustion engine is in the high-temperature state at the timeof startup.

[0208] Thus, in the case of high-temperature startup, fuel is injectedinto the combustion chamber prior to the cranking at the time ofstartup, so that the interior of the combustion chamber can be cooled byheat absorption involved in evaporation of fuel. As the cranking is yetto be performed, air-fuel mixture formed by injecting fuel into thecombustion chamber is not immediately compressed, but is allowed tosufficiently evaporate and absorb heat. Therefore, this operation willmake pre-ignition more unlikely than fuel injection at the time ofcranking.

[0209] An internal combustion engine startup-time control apparatus is astartup-time control apparatus of an internal combustion engine in whichfuel is injected into a combustion chamber, and in which an automaticstop-automatic startup control of automatically stopping a combustionoperation if an automatic stop condition is met, and of automaticallyrestarting the combustion operation if an automatic start condition ismet, is performed. The control apparatus is characterized by including apre-fuel injection setting portion that sets an injection timing of aninjection valve such that fuel is injected into the combustion chamberprior to cranking at the time of automatic startup.

[0210] In an internal combustion engine startup-time control apparatusin which automatic stop-automatic startup is performed, in particular,fuel is injected into the combustion chamber at the time of automaticstart prior to cranking, regardless of a high-temperature state.Therefore, heat absorption involved in evaporation cools the interior ofthe combustion chamber, so that pre-ignition becomes more unlikely.

[0211] An internal combustion engine stop-time control apparatus is astop-time control apparatus of an internal combustion engine in whichfuel is injected into a combustion chamber, and is characterized byincluding: a high-temperature determining portion that determineswhether the internal combustion engine is in a high-temperature state;and a during-stop fuel injection setting portion that sets an injectiontiming of an injection valve such that fuel is injected into thecombustion chamber if the high-temperature determining portiondetermines that the internal combustion engine is in thehigh-temperature state during a stop of rotation of the internalcombustion engine.

[0212] If the internal combustion engine is in the high-temperaturestate during a stop of engine rotation and the startup of the engine isinitiated during the high-temperature state, there is high possibilityof pre-ignition. Therefore, if the internal combustion engine is in thehigh-temperature state during a stop of engine rotation, the interior ofthe combustion chamber is cooled in advance by injecting fuel into thecombustion chamber. This operation reduces the likelihood ofpre-ignition occurring at the time of startup.

[0213] In the above-described construction of the internal combustionengine stop-time control apparatus, the during-stop fuel injectionsetting portion may make a setting such that fuel is injected into thecombustion chamber if the high-temperature determining portiondetermines that the internal combustion engine is in thehigh-temperature state immediately after the internal combustion enginestops rotating in association with a stop of a combustion operation.

[0214] After the internal combustion engine stops turning, thetemperature in the combustion chamber immediately starts to rise upon astop of the cooling device of the internal combustion engine. Therefore,if the engine has high temperature when the engine stops rotating, thetemperature of the engine is expected to further rise. Furthermore, itis not known when startup is performed. Therefore, fuel injection timingis set at timing immediately following a stop of rotation of theinternal combustion engine, so that pre-ignition is more effectivelyprevented.

[0215] An internal combustion engine startup-time control apparatus is astop-time control apparatus of an internal combustion engine in whichfuel is injected into a combustion chamber, and in which an automaticstop-automatic startup control of automatically stopping a combustionoperation if an automatic stop condition is met, and of automaticallyrestarting the combustion operation if an automatic start condition ismet, is performed. The control apparatus is characterized by including astop-time fuel injection setting portion that sets an injection timingof an injection valve such that fuel is injected into the combustionchamber immediately after rotation of the internal combustion engine isstopped due to the automatically-caused stop of combustion operation.

[0216] Due to setting such that fuel is injected into the combustionchamber immediately after rotation of the internal combustion engine isstopped by the automatic stop, it is possible to prevent the internalcombustion engine from having further increased temperature. Therefore,automatic startup of the engine during the high-temperature state can beprevented. Therefore, pre-ignition can be made more unlikely.

[0217] The method of the invention may be applied as a program that iscaused to function as any one of the control apparatuses describedabove, or a record medium that stores the program in such a fashion thatthe program can be read by a computer. The record medium may be ofvarious forms, including a CD-ROM, a floppy disk, a DVD-ROM, etc. Therecord medium may also be a computer-readable program transmissionmedium that is caused to function as a control apparatus.

[0218] While the invention has been described with reference to what arepresently considered to be preferred embodiments thereof, it is to beunderstood that the invention is not limited to the disclosedembodiments or constructions. To the contrary, the invention can becarried out in forms without departing from the spirit of the invention.

What is claimed is:
 1. A startup-time control apparatus of an internalcombustion engine in which fuel is injected into a combustion chamber,comprising: a high-temperature startup determining portion thatdetermines whether the internal combustion engine is in ahigh-temperature state at a time of startup of the internal combustionengine; and a fuel injection start timing setting portion that sets aninjection timing of an injection valve such that fuel injection startsafter a delay period elapses following a start of cranking if thehigh-temperature startup determining portion determines that theinternal combustion engine is in the high-temperature state at the timeof startup.
 2. The control apparatus according to claim 1, wherein thedelay period is a length of time that is needed for an engine coolingwater present outside the engine immediately prior to the start ofcranking to reach a surrounding of the combustion chamber and reduce atemperature in the combustion chamber.
 3. A startup-time controlapparatus of an internal combustion engine in which fuel is injectedinto a combustion chamber, and in which an automatic stop-automaticstartup control of automatically stopping a combustion operation if anautomatic stop condition is met, and of automatically restarting thecombustion operation if an automatic start condition is met, isperformed, the control apparatus comprising: an automatic startupdetermining portion that determines whether the combustion operation hasbeen automatically restarted; and a fuel injection start timing settingportion that sets an injection timing of an injection valve such thatfuel injection starts after a delay period elapses following a start ofcranking if the automatic startup determining portion determines thatthe combustion operation is automatically restarted.
 4. The controlapparatus according to claim 3, wherein the delay period is a length oftime that is needed for an engine cooling water present outside theengine immediately prior to the start of cranking to reach a surroundingof the combustion chamber and reduce a temperature in the combustionchamber.
 5. A startup-time control apparatus of an internal combustionengine in which fuel is injected into a combustion chamber, comprising:a high-temperature startup determining portion that determines whetherthe internal combustion engine is in a high-temperature state at a timeof startup of the internal combustion engine; and a startup-time fuelinjection amount setting portion that sets a smaller amount of fuelinjection at a time of startup if the high-temperature startupdetermining portion determines that the internal combustion engine is inthe high-temperature state at the time of startup than if the internalcombustion engine is not in the high-temperature state at the time ofstartup.
 6. A startup-time control apparatus of an internal combustionengine in which fuel is injected into a combustion chamber, and in whichan automatic stop-automatic startup control of automatically stopping acombustion operation if an automatic stop condition is met, and ofautomatically restarting the combustion operation if an automatic startcondition is met, is performed, the control apparatus comprising: anautomatic startup determining portion that determines whether thecombustion operation has been automatically restarted; and astartup-time fuel injection amount setting portion that, if theautomatic startup determining portion determines that the combustionoperation has been automatically restarted, sets an amount of fuelinjection at a time of startup as an amount that is smaller than theamount of fuel injection set at a time of startup caused by a startupoperation performed by an operator.
 7. A startup-time control apparatusin which fuel injection into a combustion chamber and fuel injectioninto an intake passage are possible, comprising: a high-temperaturestartup determining portion that determines whether the internalcombustion engine is in a high-temperature state at a time of startup ofthe internal combustion engine; and a startup-time fuel injectionselecting portion which accomplishes the fuel injection at the time ofstartup by performing the fuel injection into the combustion chamber orthe fuel injection into both the combustion chamber and the intakepassage if the high-temperature startup determining portion determinesthat the internal combustion engine is not in the high-temperature stateat the time of startup, and which accomplishes the fuel injection at thetime of startup by performing the fuel injection into the intake passageif the high-temperature startup determining portion determines that theinternal combustion engine is in the high-temperature state at the timeof startup.
 8. A startup-time control apparatus of an internalcombustion engine in which fuel injection into a combustion chamber andfuel injection into an intake passage are possible, and in which anautomatic stop-automatic startup control of automatically stopping acombustion operation if an automatic stop condition is met, and ofautomatically restarting the combustion operation if an automatic startcondition is met, is performed, the control apparatus comprising: anautomatic startup determining portion that determines whether thecombustion operation has been automatically restarted; and astartup-time fuel injection selecting portion which accomplishes thefuel injection at the time of startup by performing the fuel injectioninto the combustion chamber or the fuel injection into both thecombustion chamber and the intake passage if the startup is other than acase where the automatic startup determining portion determines that thecombustion operation has been automatically restarted, and whichaccomplishes the fuel injection at the time of startup by performing thefuel injection into the intake passage if the automatic startupdetermining portion determines that the combustion operation has beenautomatically restarted.
 9. A stop-time control apparatus of an internalcombustion engine in which fuel is injected into a combustion chamber,and in which an automatic stop-automatic startup control ofautomatically stopping a combustion operation if an automatic stopcondition is met, and of automatically restarting the combustionoperation if an automatic start condition is met, is performed, thecontrol apparatus comprising: a high-temperature stop determiningportion that determines whether the internal combustion engine is in ahigh-temperature state when the automatic stop condition is met; and anautomatic stop execution control portion which executes automatic stopof the combustion operation if the high-temperature stop determiningportion determines that the internal combustion engine is not in thehigh-temperature state when the automatic stop condition is met, andwhich prohibits the automatic stop of the combustion operation if thehigh-temperature stop determining portion determines that the internalcombustion engine is in the high-temperature state when the automaticstop condition is met.
 10. A stop-time control apparatus of an internalcombustion engine in which fuel is injected into a combustion chamber,and in which an automatic stop-automatic startup control ofautomatically stopping a combustion operation if an automatic stopcondition is met, and of automatically restarting the combustionoperation if an automatic start condition is met, is performed, thecontrol apparatus comprising: an automatic stop determining portion thatdetermines whether the combustion operation has been automaticallystopped; and a pre-startup cooling portion that drives a cooling deviceof the internal combustion engine to cool the internal combustion engineduring a stop of the combustion operation if the automatic stopdetermining portion determines that the combustion operation has beenautomatically stopped.
 11. The control apparatus according to claim 10,wherein the pre-startup cooling portion drives the cooling device of theinternal combustion engine by electric energy.
 12. The control apparatusaccording to claim 10, further comprising a high-temperature determiningportion that determines whether the internal combustion engine is in ahigh-temperature state, wherein the pre-startup cooling portion drivesthe cooling device of the internal combustion engine if thehigh-temperature determining portion determines that the internalcombustion engine is in the high-temperature state during anautomatically-caused stop of the combustion operation.
 13. Astartup-time control apparatus of an internal combustion engine in whichfuel is injected into a combustion chamber, comprising: ahigh-temperature startup determining portion that determines whether theinternal combustion engine is in a high-temperature state at a time ofstartup; and a pre-fuel injection setting portion that sets an injectiontiming of an injection valve such that fuel is injected into thecombustion chamber prior to cranking if the high-temperature startupdetermining portion determines that the internal combustion engine is inthe high-temperature state at the time of startup.
 14. A startup-timecontrol apparatus of an internal combustion engine in which fuel isinjected into a combustion chamber, and in which an automaticstop-automatic startup control of automatically stopping a combustionoperation if an automatic stop condition is met, and of automaticallyrestarting the combustion operation if an automatic start condition ismet, is performed, the control apparatus comprising: an automaticstartup determining portion that determines whether the combustionoperation has been automatically restarted; and a pre-fuel injectionsetting portion that sets an injection timing of an injection valve suchthat fuel is injected into the combustion chamber prior to cranking ifthe automatic startup determining portion determines that the combustionoperation has been automatically restarted.
 15. A stop-time controlapparatus of an internal combustion engine in which fuel is injectedinto a combustion chamber, comprising: a high-temperature determiningportion that determines whether the internal combustion engine is in ahigh-temperature state; and a during-stop fuel injection setting portionthat sets an injection timing of an injection valve such that fuel isinjected into the combustion chamber if the high-temperature determiningportion determines that the internal combustion engine is in thehigh-temperature state during a stop of rotation of the internalcombustion engine.
 16. The control apparatus according to claim 15,wherein the during-stop fuel injection setting portion sets an injectiontiming of an injection valve such that fuel is injected into thecombustion chamber if the high-temperature determining portiondetermines that the internal combustion engine is in thehigh-temperature state immediately after the internal combustion enginestops rotating in association with a stop of a combustion operation. 17.A stop-time control apparatus of an internal combustion engine in whichfuel is injected into a combustion chamber, and in which an automaticstop-automatic startup control of automatically stopping a combustionoperation if an automatic stop condition is met, and of automaticallyrestarting the combustion operation if an automatic start condition ismet, is performed, the control apparatus comprising: an automatic stopdetermining portion that determines whether the combustion operation hasbeen automatically stopped; and a stop-time fuel injection settingportion that sets an injection timing of an injection valve such thatfuel is injected into the combustion chamber immediately after a stop ofrotation of the internal combustion engine if the automatic stopdetermining portion determines that the combustion operation has beenautomatically stopped.
 18. A startup-time control method of an internalcombustion engine in which fuel is injected into a combustion chamber,comprising determining whether the internal combustion engine is in ahigh-temperature state at a time of startup of the internal combustionengine; and setting an injection timing of an injection valve such thatfuel injection starts after a delay period elapses following a start ofcranking if it is determined that the internal combustion engine is inthe high-temperature state at the time of startup.
 19. The controlmethod according to claim 18, wherein the delay period is a length oftime that is needed for an engine cooling water present outside theengine immediately prior to the start of cranking to reach a surroundingof the combustion chamber and reduce a temperature in the combustionchamber.
 20. A startup-time control method of an internal combustionengine in which fuel is injected into a combustion chamber, and in whichan automatic stop-automatic startup control of automatically stopping acombustion operation if an automatic stop condition is met, and ofautomatically restarting the combustion operation if an automatic startcondition is met, is performed, the control method comprising: settingan injection timing of an injection valve such that fuel injectionstarts after a delay period elapses following a start of cranking if thecombustion operation is automatically restarted.
 21. The control methodaccording to claim 20, wherein the delay period is a length of time thatis needed for an engine cooling water present outside the engineimmediately prior to the start of cranking to reach a surrounding of thecombustion chamber and reduce a temperature in the combustion chamber.22. A startup-time control method of an internal combustion engine inwhich fuel is injected into a combustion chamber, comprising:determining whether the internal combustion engine is in ahigh-temperature state at a time of startup of the internal combustionengine; and setting a smaller amount of fuel injection at a time ofstartup if it is determined that the internal combustion engine is inthe high-temperature state at the time of startup than if the internalcombustion engine is not in the high-temperature state at the time ofstartup.
 23. A startup-time control method of an internal combustionengine in which fuel is injected into a combustion chamber, and in whichan automatic stop-automatic startup control of automatically stopping acombustion operation if an automatic stop condition is met, and ofautomatically restarting the combustion operation if an automatic startcondition is met, is performed, the control method comprising: setting asmaller amount of fuel injection when the combustion operation isautomatically restarted than when startup is caused by a startupoperation performed by an operator.
 24. A startup-time control method inwhich fuel injection into a combustion chamber and fuel injection intoan intake passage are possible, comprising: determining whether theinternal combustion engine is in a high-temperature state at a time ofstartup of the internal combustion engine; accomplishing the fuelinjection at the time of startup by performing the fuel injection intothe combustion chamber or the fuel injection into both the combustionchamber and the intake passage if it is determined that the internalcombustion engine is not in the high-temperature state at the time ofstartup; and accomplishing the fuel injection at the time of startup byperforming the fuel injection into the intake passage if it isdetermined that the internal combustion engine is in thehigh-temperature state at the time of startup.
 25. A startup-timecontrol method of an internal combustion engine in which fuel injectioninto a combustion chamber and fuel injection into an intake passage arepossible, and in which an automatic stop-automatic startup control ofautomatically stopping a combustion operation if an automatic stopcondition is met, and of automatically restarting the combustionoperation if an automatic start condition is met, is performed, thecontrol method comprising: accomplishing the fuel injection at the timeof startup by performing the fuel injection into the combustion chamberor the fuel injection into both the combustion chamber and the intakepassage if the startup is other than a case where the combustionoperation is automatically restarted; and accomplishing the fuelinjection at the time of startup by performing the fuel injection intothe intake passage if the combustion operation is automaticallyrestarted.
 26. A stop-time control method of an internal combustionengine in which fuel is injected into a combustion chamber, and in whichan automatic stop-automatic startup control of automatically stopping acombustion operation if an automatic stop condition is met, and ofautomatically restarting the combustion operation if an automatic startcondition is met, is performed, the control method comprising:determining whether the internal combustion engine is in ahigh-temperature state when the automatic stop condition is met;executing automatic stop of the combustion operation if it is determinedthat the internal combustion engine is not in the high-temperature statewhen the automatic stop condition is met; and prohibiting the automaticstop of the combustion operation if it is determined that the internalcombustion engine is in the high-temperature state when the automaticstop condition is met.
 27. A stop-time control method of an internalcombustion engine in which fuel is injected into a combustion chamber,and in which an automatic stop-automatic startup control ofautomatically stopping a combustion operation if an automatic stopcondition is met, and of automatically restarting the combustionoperation if an automatic start condition is met, is performed, thecontrol method comprising: driving a cooling device of the internalcombustion engine to cool the internal combustion engine during anautomatically-caused stop of the combustion operation.
 28. The controlmethod according to claim 27, wherein the pre-startup cooling portiondrives the cooling device of the internal combustion engine by electricenergy.
 29. The control method according to claim 27, furthercomprising: determining whether the internal combustion engine is in ahigh-temperature state; and driving the cooling device of the internalcombustion engine if it is determined that the internal combustionengine is in the high-temperature state during an automatically-causedstop of the combustion operation.
 30. A startup-time control method ofan internal combustion engine in which fuel is injected into acombustion chamber, comprising: determining whether the internalcombustion engine is in a high-temperature state at a time of startup;and setting an injection timing of an injection valve such that fuel isinjected into the combustion chamber prior to cranking if it isdetermined that the internal combustion engine is in thehigh-temperature state at the time of startup.
 31. A startup-timecontrol method of an internal combustion engine in which fuel isinjected into a combustion chamber, and in which an automaticstop-automatic startup control of automatically stopping a combustionoperation if an automatic stop condition is met, and of automaticallyrestarting the combustion operation if an automatic start condition ismet, is performed, the control method comprising: setting an injectiontiming of an injection valve such that fuel is injected into thecombustion chamber prior to cranking at a time of an automatic startup.32. A stop-time control method of an internal combustion engine in whichfuel is injected into a combustion chamber, comprising: determiningwhether the internal combustion engine is in a high-temperature state;and setting an injection timing of an injection valve such that fuel isinjected into the combustion chamber if it is determined that theinternal combustion engine is in the high-temperature state during astop of rotation of the internal combustion engine.
 33. The controlmethod according to claim 32, wherein a setting the injection valve suchthat fuel is injected into the combustion chamber if it is determinedthat the internal combustion engine is in the high-temperature stateimmediately after the internal combustion engine stops rotating inassociation with a stop of a combustion operation.
 34. A stop-timecontrol method of an internal combustion engine in which fuel isinjected into a combustion chamber, and in which an automaticstop-automatic startup control of automatically stopping a combustionoperation if an automatic stop condition is met, and of automaticallyrestarting the combustion operation if an automatic start condition ismet, is performed, the control method comprising: setting an injectiontiming of an injection valve such that fuel is injected into thecombustion chamber immediately after rotation of the internal combustionengine is stopped by an automatic stop of the combustion operation. 35.A medium storing a program for executing the method described in claim18.
 36. A medium storing a program for executing the method described inclaim
 19. 37. A medium storing a program for executing the methoddescribed in claim
 20. 38. A medium storing a program for executing themethod described in claim
 21. 39. A medium storing a program forexecuting the method described in claim
 22. 40. A medium storing aprogram for executing the method described in claim
 23. 41. A mediumstoring a program for executing the method described in claim
 24. 42. Amedium storing a program for executing the method described in claim 25.43. A medium storing a program for executing the method described inclaim
 26. 44. A medium storing a program for executing the methoddescribed in claim
 27. 45. A medium storing a program for executing themethod described in claim
 28. 46. A medium storing a program forexecuting the method described in claim
 29. 47. A medium storing aprogram for executing the method described in claim
 30. 48. A mediumstoring a program for executing the method described in claim
 31. 49. Amedium storing a program for executing the method described in claim 32.50. A medium storing a program for executing the method described inclaim
 33. 51. A medium storing a program for executing the methoddescribed in claim 34.